Method of making a wear blade for an oil drilling tool

ABSTRACT

A method of making oil drilling tools, particularly stabilizers, and wear blades therefor. The blades are made and dressed on a separate former to avoid pre-heating the tool body. They are then welded to the tool body by a low heat electric welding technique and are arranged around the body equally spaced and skewed in an anti-clockwise direction, the total circumferential coverage being complete. Typically there are four blades each skewed 90*.

ilnited States Patent Groom [54] METHOD OF MAKING A WEAR BLADE FOR ANOIL DRILLING TOOL [72] Inventor: William James Groom, Belton, England[73] Assignee: Lion Oil Tool Holdings (International) Limited, GreatYarmouth, Norfolk, England [22] Filed: Nov. 3, 1969 21 Appl. No.:873,370

2,964,420 12/1960 Poorman et a1 ..1 17/127 X 1 51 May 9,1972

3,505,101 '4/1970 Kofisky et a1. ..117/127 X 848,161 3/1907 Dierig..29/484 X 2,515,191 7/1950 Carpenter et al..... ...29/471 1 3,248,7885/1966 Goldstein et al.. ..29/493 3,258,955 7/1966 Lindsay 29/423 X3,453,719 7/1969 Feinstra ..29/472 9 3,535,767 10/1970 Doherty, Jr. etal. ..29/497.5 X

Primary Examiner-John F. Campbell Assistant Examiner-Richard BernardLazarus Att0rney-Wenderoth, Lind & Ponack 57 ABSTRACT A method of makingoil drilling tools, particularly stabilizers, and wear blades therefor.The blades are made and dressed on a separate former to avoidpre-heating the tool body. They are then welded to the tool body by alow heat electric welding technique and are arranged around the bodyequally spaced and skewed in an anti-clockwise direction, the totalcircumferentialcoverage being complete. Typically there are four bladeseach skewed 90.

4 Claims, 4'Drawing Figures P'ATENTEB M 9 I912 3, 660,889

FIG. 7.

y [IIIIIII WILLIAM JAMES GROOM, Inventor BY 'A/A/ZLM Z, M

Attorneys METHOD OF MAKING A WEAR BLADE FOR AN OIL DRILLING TOOL Theinvention relates to oil drilling tools, namely to tools for use indrilling for oil or natural gas. Particular application for theinvention is found in stabilizers, turbine drills and pipecutting tools.

Oil drilling tools are subject to severe wear and are generally providedwith facings of hard, wear resistant metal applied to the steel body ofthe tool. Problems are presented by the initial application of suchfacings and more particularly by the replacement of worn facings. Thepresent invention seeks to alleviate these problems.

According to the invention there is provided a method of making a wearblade for an oil drilling tool consisting in forming on a cylindricalformer a blade base which comprises a length of steel of substantiallyrectangular cross-section extending along the former and skewed aroundit in an anticlockwise direction substantially 90 or less; applying adressing of hard wear material to the outer face of the base; andremoving the completed blade from the former.

The hard wear material may comprise hard metal carbides bonded in amatrix of brass, the carbides representing preferably 60 to 90 percentor more of the total.

The invention includes within its scope a wear blade when made by theforegoing method and also a method of dressing an oil drilling tool witha plurality of such wear blades, which method consists in applying theblades to a cylindrical steel body part of the tool of the samedimensions as the former and electrically welding the blades to the bodypart with the use of a low heat input electrode, a welding techniquebeing used which requires preheating to no more than about 300 C, theblades being evenly spaced apart and the number of blades being chosenin relation to their angle of skew so that the blades cover the completecircumference of the body part.

Preferably the electrode is a low heat input high elongation electrodeof hydrogen-controlled austeno-ferritic structure.

The method may be used in the replacement of worn blades and as animportant aspect of the invention it is proposed that in applying newfacings to an oil drilling tool the worn facings are not removed but newblades in accordance with the invention are welded in place adjacent theold facings. Indeed, it may be expedient to increase theeffective gaugesize of the tool by applying new, thicker blades in this way even if theold blades are not worn.

Preferably the total circumferential coverage of the blades is 360"; itmay be rather more but shouldbe no less. In a preferred embodiment thereare four blades each skewed 90. However, there may be more than fourblades perhaps'as many as eight. Such blades would be correspondinglynarrower and would be correspondingly skewed less. For example, in asix-bladed arrangement each blade would be skewed some 60.

The invention will further be described with reference to theaccompanying drawings, of which:

FIGS. 1 and 2 are schematic diagrams illustrating respectively themanufacture of a wear blade and the application of the blade to a toolin accordance with the invention;

FIG. 3 is a plan view of an oil drilling tool in accordance with theinvention; and

FIG. 4 is a plan view of a wear blade in accordance with the invention.

Referring to FIG. 1 the wear blade is made by forming a mild-steel base1 on a cylindrical former 2 and dressing one side of the base by brazingto it a facing 3 of hard wear material. ION ALLOY overlay rods and IONUXflux are used to braze the facing 3 to the base 1. The hard wearmaterial may be that known as IONITE, which is comprised of fragments ofsintered tungsten carbides with additives of titanium, tantalum andother hard metal carbides bonded with cobalt in a brass base, theproportions of carbides to base being in the range 60 to 90 percent ormore of the whole. Subject to the maintenance of adequate stability, thehigher the proportion Vickers diamond pyramid hardness. The thickness ofthe facing 3 is about one-fourthinch. The former 2 is the same size andshape as the tool to which the blade is to be applied. In this case thetool is a stabilizer. After forming, the blade is removed from theformer.

Referring now to FIG. 2 the blade of FIG. 1 is shown applied to the body4 of the stabilizer. The body is of EN 24T or EN 19T heat treated steeland the base I is welded thereto by means of a low temperature electricwelding technique. Electrodes of the kind known as IONECT special lowheat, maximum elongation electrodes are used to weld the blade to thebody 4, the weld metal being shown at 5 in FIG. 2. The IONECT" electrodeis of hydrogen controlled austeno-ferritic structure. The weldingprocess requires a pre-heating temperature of normally no more than 250C and certainly no more than 300 C.

FIG. 3 shows a stabilizer fitted with the blades. The tool has a fishingneck 6 some 28 inches long, an upset portion 7, 18 inches long and anose 8, 20 inches long. The cylindrical upset portion is provided withfour blades 9, each extending from end to end of portion 7 and skewedaround the upset portion through in an anti-clockwise sense. The fourblades together thus extend around the whole circumference.

FIG. 4 shows the nature of a blade. Each blade comprises a steel base 10provided with a tungsten carbide facing 1 1. From the fishing" neck endthe blade is of even thickness for the first 12 inches to 14 inches,whereafter it tapers downwardly in thickness to the nose end. The bladesare welded to the upset portion 7 in the manner described with referenceto FIG. 2.

It will be seen that when the blades wear down, or if perhaps theeffective outside diameter of the tool is to be increased, new orthicker blades may be welded into position adjacent and between the oldblades.

Use of the invention as exemplified in the foregoing description madewith reference to the accompanying drawings has many advantages.Firstly, it is found that the tools have a particularly long life.Secondly, the wear blades, being capable of being welded to the drillingtools by low temperature techniques, offer the possibility ofapplication to the tools on side at the drilling rig. This means thatspares may be held more readily, freight costs are reduced and so is theout-of-service time for a particular tool. Also, spares with a range ofinside and outside diameters may be kept to cover a range of possibleapplications. Furthermore, the tool is not subjected to the hightemperatures normally applied for welding, dressing or re-dressing thehard facing metal. This often requires high temperature pre-heating andpost-heating to stressrelieve the welds, resulting in deterioration ofthe blade and tool body by undesired heat treatment. The lower weldingtemperatures used in the preferred method above described do notappreciably affect the hardness of the tool body.

I claim:

l. A method of making a wear blade for an oil drilling tool consistingin forming on a cylindrical former a blade base which comprises a lengthof steel of substantially rectangular cross-section extending along theformer and skewed around it in an anti-clockwise direction at mostsubstantially 90; applying a dressing of hard wear material to the outerface of the base; and removing the completed blade from the former.

2. A method as claimed in claim 1 wherein the hard wear material iscomposed of hard metal carbides bonded in a matrix of brass, thecarbides representing 60 to 90 percent or more of the total.

3. A method as claimed in claim 2 wherein the hard wear material isbrazed to the base.

4. A method as claimed in claim 1 wherein the hardness of the hard wearmaterial is between 950 and 1850 Vickers diamond pyramid'hardness.

1. A method of making a wear blade for an oil drilling tool consistingin forming on a cylindrical former a blade base which comprises a lengthof steel of substantially rectangular crosssection extending along theformer and skewed around it in an anti-clockwise direction at mostsubstantially 90*; applying a dressing of hard wear material to theouter face of the base; and removing the completed blade from theformer.
 2. A method as claimed in claim 1 wherein the hard wear materialis composed of hard metal carbides bonded in a matrix of brass, thecarbides representing 60 to 90 percent or more of the total.
 3. A methodas claimed in claim 2 wherein the hard wear material is brazed to thebase.
 4. A method as claimed in claim 1 wherein the hardness of the hardwear material is between 950 and 1850 Vickers diamond pyramid hardness.